Testing or inspecting machine



P 21, 1936- H. D. STEPHENS 2,038,012

TESTING OR INSPECTING MACHINE v Filed Jah. 24, 1933 s Sheets-Sheet 1 FIG; 3

INVENTOR. HflRRY D. SZEPh'E/VS,

BY 19/5 HTTOR Ex I April 21, 1936- H. o. STEPHENS 2,033,012

TESTING OR INSPECTING MACHINE Filed Jan. 24, 1933 3'Sheets-Sheet 2 4 INVENTOR. L .5 Hfi/FR'X a STEPHEN;

L m v HIS HTTOR'NEL 21, 1936- H. D. STEPHENS TESTING 0R INSPECTING MACHINE 7 Filed Jan. 24, 1935 3 Sheets-Sheet 3 INVEN TOR.

HHRRY .0. STEPHEN-S,

HA5 6' TTOIFNEY.

Patented Apr. 21, 1936 TESTING 0R INSPECTING MACHINE Harry D. Stephens, Bristol, Conn., assignor, by mesne assignments, to General Motors Corporation, Detroit, Micln, a corporation of Delaware Application January 24, 1933, Serial No; 853,281

7 Claims. (01. 175-183) UNITED STATES PATENT OFFICE This invention relates to testing or inspecting machines and comprises all of the features of novelty herein disclosed. An object of the invention is to provide an improved machine and method for testing articles, especially steel arti-- cles, to detect soft spots or the lack of uniformity in hardness. Another object is to provide a machine utilizing the ma etic properties or permeability of the metal to indicateits uniformity or lack of uniformity in structure. Another object is to provide improved apparatus for supporting and rotating round articles to subject them to a test. 7

To these ends and also to improve generally upon machines of this character, the invention consists in the various matters hereinafter described and claimed. In its broader aspects, the invention is not necessarily limited to the specific construction selected for illustrative purposes in the accompanying drawings in which Fig. 1 is a sectional view on the line -|l of Fig. 6 with some parts in side elevation.

Fig. 2 is an enlarged view ofcertain levers with a portion of theirsupporting bracket in section.

Fig. 3 is an enlarged side view of a-plunger and associated parts.

Fig. 4 is a front view of the plunger and its I2 is preferably composed of felt compressed and bolted between metal side discs l4, and the idler rollers l0 are preferably of'brass. The driving roller.;l2 is fixed to the front end of a drive shaft I 6 which is journalled in bearing blocks I8 on the top of a bracket 20. The bracket has a vertical web 2| joined to vertical bosses or sleeves 22 (Fig. 6) which are adjustably secured by setscrews 24 toupright posts 26 on a frame 28 having supporting legs 30. As will appear, the shaft can be clutched to a cam which operates a series of control switches. I

The idler rollers iii are 'journalled between side rails 32 of a yleldable carrier (Figs. 5 and 6) which can be raised and lowered to provide for inserting or removing the work. The ends of the rails 32 are connected by blocks 34 supported on plungers 36 which are guided vertically by openings in lugs 38 and 40 on the frame. Coil springs 42 are interposed between the lugs 40 and abutment washers 44 on the plungers whereby the idler rollers are urged yieldingly upwards against the work and so hold the work against the friction driving roller l2. The lower ends of the plungers are shouldered and secured by nuts 45 to a cross bar 46 having connection with a treadle. Depending lugs 48 on the cross bar are pivoted by a pin 50 to an arm 52 (Fig. 1)

on a treadle lever 54, the lever being pivoted on a shaft-56 secured in depending lugs 58 onthe frame. Sleeves surround the shaft and serve to space the lever from the lugs. An upright arm 62 on the lever is connected by a coil spring 64 to a screw 66 adjustably anchored on a frame part 68. The coil spring 64 urges the treadle lever counterclockwise in Fig. 1 and resulting upward movement of the idler rollers, when there is no work in the machine, is limited by the engagement of the cross bar 46 with the frame lugs 40.

A transformer, having a primary coil I0 and two pairs of secondary coils 12 and I4, is yieldably supported from the cross bar 46, and the core laminations'lB pertaining to the upper pair of secondary coils 12 are urged againstthe rotating work-piece which thereby completes-a path for the magnetic flux. The laminations 16 have their upperends unconnected and free to project between the side rails 32 and are desirably shaped to conform to theperiphery of the work-piece. The laminations are united or continuous at their lower ends so that the magnetic field pertaining to the lower pair of secondary coils" is a constant. The transformer parts are heldin a yoke by clamping plates 82. The yoke has vertical openings at its ends to slide on plungers 84 whose lower ends are shouldered and clamped by nuts 86 to thecross bar 46. Coil springs 88, interposed between the yoke ends and collars 90 on the plungers, urge the transformer parts upwardly until the laminations 16 engage the work-piece.

Power for driving the roller I2 is supplied from a motor I00 to speed reducing gearing in a' casing I02 from which projects a countershaft I04 having'a sprocket wheel I06 engaging a sprocket A chain I08 which drives a sprocket wheel I I 0 on the shaft I 6. Splined on the shaft "5 is a grooved clutch collar H2 having clutch teeth arranged to engage co-operating teeth on a cam. H4 whose, hub is loosely journalled on the shaft Hi. When the clutch is thrown in by mechanism hereinafter described, the cam makes one revolution and actuat'es a series of controlling switches. The cam projects downwardly through a slot in the bracket 20 and engages a roller I I8 journalled in a fork I I8 at the upper end of a sliding plunger I20 which is guided vertically by guide brackets I22 fastened on the vertical web 2| of the bracket 20. The plunger is urged upwardly by a coil spring I24 interposed between one of the brackets I22 and an abutment I20 on the plunger. Projecting laterally from the fork II8 (see Fig. 3), through a slot I28 in the web 2|, is a bar I80 which is tapped to receive an adjustable screw I82 having a lock nut I84, The lower end of the screw abuts against a plate I28 fastened to a block I88 which is pivoted on a'shaft I40 mounted in lugs I42 on the web 2I of the bracket 20. Acoil spring I44 holds the plate I88 against the screw I82 so that the block I80 will rock or tilt with a vertical movement of the plunger I20. Held by spring clips I48 on the tiltable block I88 is a series of mercury switches indicated on the diagram by numerals I80, I52'and I84. that one revolution of the cam III will tilt the mercury switches, first from a normal position and then back again.

In order to throw the clutch to start the rotation of the cam, the following mechanism is provided. (See Figs. 1, 2 and '6.) Rollers I88 project into a groove of the clutch collar II2 from arms I88 which are pinned to rock shafts I88 journalled in lugs on the top of the bracket 20. Arms I82 are also pinned to the rock shafts and project downwardly through holes in the bracket 20. The lower ends of the arms I02 are slotted to provide lost-motion pivot connections with pivot pins I84 .carried by levers I08 which are pivoted at I81 to lugs IGB'depending from the bracket 28. Each lever I88 is'pivoted to one of the arms of a yoke I10 which straddles the lower portion of a solenoid I12 hung on the bracket 20. The middle of the yoke has an aperture for a stud I14 whose upper end is pinned loosely to the lower end of the core or plunger I18 of the solenoid. A coilspring I18 is interposed between the yoke and an adjusting nut I80 on a threaded portion of the stud I14 whereby a yielding connection is provided to compensate for a possible overrun of the solenoid plunger. From the foregoing, it'is apparent that an energizing of the solenoid will act through the yoke and lever system to throw in the clutch and start rotation of the cam I I4. The switches will thus be tilted, 'under control of the cam, first in one direction and then in the other. The

switches control a cycle of the machine.

Referring to the diagram, the driving motor I is started by closing a switch I8I to complete a circuit in line wires I82 and I04. A pilot light or signal lamp I88 is lit by closing a switch I88 and this light indicates that current is being supplied to the testing instruments. One of the instruments made ready for action is a transformer I90 controlling a lamp I82 in a circular casing I94 and another is the field winding I98 of an alternating current reflecting galvanometer I88 having a mirror 200 and an armature winding 202. The lamp casing I9 4 has a small hole 284 bisected by a wire 208 on an apertured plate 288. A circular ray of light with a bisecting shadow is thus directed through a lens 2I0 to the mirror 200 and is reflected to a frosted glass 2I2 having a marker 2 I4 to indicate a neutral position. The lens 2I0 is suitably held in a vertically adjusted position by a screw 2I8 on the vertical leg of an angle bracket 220 which is slotted and held in cam Thus it willbe seen horizontally adjusted position on a plate 222 by a clamping screw 224. These instruments are contained in a box 228 (Fig. 6) supported by posts 228 from the bracket 20.

Upon actuating the treadle lever 84, a workpiece W can be placed between the rollers for rotation. To start a cycle for testing the piece, a push button switch 280 is actuated momentarily and this energizes the solenoid I12 and throws in the clutch II2 for rotating the cam H4. The

quickly depresses the plunger I20, and the switches I80 and I84 are closed, and switch I82 (which is normally closed) is opened. The switch I82 is normally closed for the purpose of -,shortcircuiting the armature windings 202 and is set to open just after the switch I84 is closed in order to prevent abnormal needle deflection during the instant of building up magnetizing current. When the switch I52 is opened, the position of the mirror is controlled by the condition of the work-piece as will appear. The closing of the switch I50 by the cam holds the solenoid active after the push button switch 280 is released and this condition is maintained until the completion of one revolution of the cam opens the switch and de-energizes the solenoid. The roller I4 makes one revolution and is of a selected diameter larger than the work-piece so as to insure at least a full revolution of the work-piece during the testing cycle.

When the remaining switch I04 is closed by the cam, a circuit is completed through the primary winding and through a condenser 232 which governs the amount of current in the primary and the phase relationship of that current to the current in the galvanometer field. An ammeter 284 is also in this circuit. The secondary windings 12 have an induced current which is influenced by the lack of uniformity in hardness of the work-piece W engaging their laminations 18. In the preliminary set up, a master work-piece of acceptable hardness and uniformity is placed in the flux fleld of the secondary windings 12 and potentiometers 288 and 238 are adjusted until the flow, of currents in both secondary windings 12 and 14 balance one another with the mirror in a neutral position with the reflected shadow at the marker 2 I4. A resistance 240 is placed in the circuit of the secondary windings 12 to prevent burning out the armature windings 282 and a similar resistance 242 is placed in the circuit of the secondary windings 14. A variable shunt 244 is placed across the terminals ofthe armature windings 202 to shunt excessive current from the armature. If the piece being tested lacks the uniformity in hardness required for an acceptable article, its permeability or some other physical property will vary from the standard and the lack of balance in the currents of the secondary windings 12 and 14 will cause the mirror 202 to swing. The reflected image will swing to one side or the other of the marker 2 and furnish a visual indication of the amount of variation in hardness so that the operator can determine whether to reject thev piece. Not only is variation in hardness at different portions of the piece indicated but if the piece as a whole varies from the master piece, that fact is also the ends of said legs; substantially as described.

2. In apparatus for testing a round work-piece,

a plurality of rollers'angularly spaced about the,

periphery of the work-piece to engage said periphery and support the work-piece for rotation, a core structure having a pair'of spaced legs engaging the periphery of the work-piece whereby a sector of the rotating work-piece magnetically connects said legs to complete a magnetic circuit, the said core also having another pair of permanently connected legs forming a constantly closed magnetic circuit independent of the work, means for producing a flow of magnetic energy in each circuit, and means for comparing said flows to determine the physical characteristics or the work sectors rotatingacfoss the first mentioned pair of legs; substantially as described.

3. In apparatus for testing around work-piece, a drivingroller and a pair of supporting rollers angularly spaced about the periphery oi the workpiece, means for urging the -supporting rollers towards the driving roller to hold the workpiece for rotation by engagement with-the periphery thereof, a testing device, means for urgdriving roller to engage the periphery of a round work-piece, a carrier having side rails, worksupporting idler rollers journalled between the side rails, plungers connected to the carrier and guiding it towards and from the driving roller, springs for urging the carrier towards the driving roller, and means for retracting the carrier; substantially as described.

5. In apparatus of the character described, a driving roller to engage the periphery of a round work-piece, a carrier having side rails, worksupporting idler rollers Journalled between the side rails, plungers connected to the carrier and guiding it towards and from the driving roller, springs for urging the carrier towards the driving roller, a work testing device yieldably connected to the carrier, and means for moving the carrierand the testing device away from the driving roller; sdbstantially as described.

6. In apparatus for testing a round work-piece, a drive shaft having a driving roller to engage the periphery of the work-piece, a testing device havvice, a cam supported by the drive shaft, a shiftable clutch for connecting the cam to the drive shaft, and a switch actuated by the cam for controlling the energizing means; substantially as described. V

'7. In apparatus for testing a round work-piece, a drive shaft having a driving roller to engage the periphery of the work-piece, atesting device having a core to engagethe periphery of the rotating work-piece, means for energizing the testing device, a switch controlling said energizing means, a shiftable clutch, a switch for controlling the clutch, and a cam driven by the clutch for controlling said switches; substantially as described.

HARRY D. STEPHENS. 

